The broad objective of this project is the development of methodology for the ultramicro analysis of prostaglandins, intermediates in their synthesis and related thromboxanes in mammalian tissues, blood plasma and platelets via chemical ionization mass spectrometry (CI-MS) employing a novel interface system alone or in combination with high performance liquid chromatography (HPLC). A feature of the interface system will be its use in conjunction with a Scott chromatographic column to provide a simple, rapid, direct analysis of prostaglandins by CI-MS. The methodology will be developed using rat platelets, mammalian kidney papillae and/or sheep vesicular gland microsomes as the enzyme sources. As substrates it is proposed to use: 5,8,11,14-20:4 (arachidonic), 8,11,14-20:3 (omega-6), 7,10,13,16-22:4 (omega-6) 4,7,10,13,16-22:5 (omega-6), 7,10,13,16-19-22:5 (omega-3) and 5,8,11,14,17-20:5 (omega-3) acids. Tritium or C-14 labelled acids will be used as substrates to identify intermediates and other compounds produced during prostaglandin synthesis in some experiments. In addition to prostaglandins, the intermediate endoperoxides and related thromboxanes will be isolated for use as reference compounds using low temperature techniques of extraction and isolation by HPLC. Unknown related compounds as might be detected by a combination of radioactivity measurements and an associated profile analysis of prostaglandins with CI-MS as a universal detector for HPLC will also be isolated. Further objectives will be the application of the methods to study the host compounds of prostaglandin precursor acids and determination of the effects on plasma and platelet prostaglandin profiles in rats fed hypercholesterolemic diets.